charging system problems

[broncobilly_69]

I had to jump start the truck the other day. I drove it about 10 miles before shutting it off. Went to start it after it sat for about 10 minutes and it wouldn't turn over, just got the sylenoid click. got a jumpstart and it idled for a good half hour before driving 10 miles back home. shut it down while I unloaded and tried to start it and again just a sylenoid click. Autozone tested the batteries for me about a month ago and they were fine. I took the alternator and the regulator in and they both tested good as well. after cleaning all the charging system and battery connections I noticed that when I turn the key on the voltage guage reads about 8 volts. when I get it jump started the guage remains at 8 volts for 30 seconds or so then it returns to 12v (normal) position could it be that my regulator or alternator cuts out once it warms up but works fine when cold (that being why they tested good)? Any other ideas what the problem might be.

 

[Mr_Roboto]

Assuming you have the 3G alternator, pull the regulator off the back and look at the brush. I had one that tested OK, but the brush was worn out so it wouldn't work "in the real world".

 

[broncobilly_69]

I have the external regulator that is mounted to the core support by the starter sylenoid. They changed in feb of 92. It sounds like you are talking about the internally regulated alternator, correct?

 

[Mr_Roboto]

Yes, sorry. You have the 2G alternator.

I get confused, my 92 VANS had the 3G alternators.

Check your quick-connectors on the alternator, they tend to overheat and loose tension. I used to have one of those alternators on my wrecker.

If you are interested in an upgrade, I did a 3G retrofit which is up in tech articles now. 130 amps and an internal regulator.

 

[broncobilly_69]

thanks, if I can't figure this thing out I may just do the upgrade to the 3G. I'm sure that will fix the problem and give me more charging power to boot.

 

[Agnem]

Do a manual "full field" test. Disconnect the plug from the voltage regulator, and short the B+ to the S connection, which I think is like the first and third wires in the connector. This will apply full power to the field and you should be seeing lots of voltage when you rev the engine. If you do, it's the voltage regulator not working.

 

[datkinsonsr]

If your batteries, alternator and regulator are in fact ok, then check all of your electrical connections on these components for corrosion. You can have a positive battery connector that looks ok, but is corroded on the contact areas. This will allow the batteries to discharge but they will not recharge. A proper charge of the batteries will take some time on a low current charger to prevent warping the plates. Check your ground connections. Are the terminals on the cables in good condition? (Poor swage). This can take time to find, but is usually something simple.